/*
 * Copyright (C) 2013 Daniel Wasilew <daniel.wasilew@codeminer.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.codeminer.parts.database.sql;

import java.util.LinkedList;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 *
 * @author Daniel Wasilew <daniel.wasilew@codeminer.org>
 */
public final class SQL {

    public static final String NON_EMPTY_CLAUSE = "you should first bring the last sql statement to an end";
    private static final Logger log = LoggerFactory.getLogger(SQL.class);
    private List<Clause> clause = new LinkedList<>();

    List<Clause> getClause() {
        return clause;
    }

    public static Select select(String... columnNames) {
        SQL sql = new SQL();
        if (!sql.clause.isEmpty()) {
            throw new IllegalStateException(NON_EMPTY_CLAUSE);
        }
        return new Select(sql, columnNames);
    }

    public static Update update(String tableName) {
        SQL sql = new SQL();
        if (!sql.clause.isEmpty()) {
            throw new IllegalStateException(NON_EMPTY_CLAUSE);
        }
        return new Update(sql, tableName);
    }

    public static Insert insertInto(String tableName) {
        SQL sql = new SQL();
        if (!sql.clause.isEmpty()) {
            throw new IllegalStateException(NON_EMPTY_CLAUSE);
        }
        return new Insert(sql, tableName);
    }

    public static Delete delete() {
        SQL sql = new SQL();
        if (!sql.clause.isEmpty()) {
            throw new IllegalStateException(NON_EMPTY_CLAUSE);
        }
        return new Delete(sql);
    }

    private SQL() {
    }

    void addClause(Clause clause) {
        this.clause.add(clause);
    }

    static boolean needsEnclosure(Object candidate) {
        return !(candidate instanceof Number);
    }
}
